1. Field of the Invention
The present invention relates to a fuel injection apparatus and particularly relates to a fuel injection apparatus for preventing an injector from moving with respect to an integrated delivery pipe in the direction of an axis of the injector, for preventing an injector side terminal from sliding with respect to a connector provided in the delivery pipe, and for preventing the decrease of sealing efficiency of fuel between the delivery pipe and the injector even if the injector is inclined with respect to the delivery pipe and is mounted to the delivery pipe.
2. Description of the Related Art
As is known in the prior art, a fuel injection apparatus has a fixing hook for preventing an injector from moving with respect to an integrated delivery pipe in a direction of an axis of the injector, and for preventing an injector side terminal from sliding with respect to a connector provided in the delivery pipe. FIG. 15 is an enlarged partial sectional view of the delivery pipe and the injector of the fuel injection apparatus of the prior art. In FIG. 15, a reference numeral 100 shows the delivery pipe molded with resin material, for connecting a fuel pump and each injector for each cylinder. A reference numeral 102 shows a delivery pipe side terminal of an electric signal line transmitting an electric signal for driving the injector. A reference numeral 104 shows a connector. A reference numeral 106 shows an injector mounting hole. A reference numeral 108 shows a fixing hook groove. A reference numeral 120 shows the injector for injecting and supplying fuel to an intake manifold 140, a valve of the injector being electrically opened or closed. A reference numeral 122 shows an O-ring for sealing a gap between the injector mounting hole 106 and the injector 120. A reference numeral 124 shows the injector side terminal. The electric signal for driving the injector is transmitted from the electric signal line of the delivery pipe to the injector 120 via the delivery pipe side terminal 102, the connector 104 and the injector side terminal 124. A reference numeral 126 shows a fixing hook for fitting in the fixing hook groove 108. A reference numeral 128 shows an insulator for sealing a gap between an injector inserting hole 142 and the injector 120.
As shown in FIG. 15, an upper end of the injector 120 is held in the injector mounting hole 106 of the delivery pipe 100 via the O-ring 122. A lower end of the injector 120 is held in the injector inserting hole 142 of the intake manifold 140 via the insulator 128. While fuel is injected, the injector 120 is forced downwardly by fuel pressure. However, the injector 120 is prevented from moving with respect to the delivery pipe 100 in the direction of the axis of the injector, because a lower face of the fixing hook 126 contacts a lower face of the fixing hook groove 108. Therefore, the sliding of an electrically contacting point between the connector 104 and the injector side terminal 124 is prevented, and the increase of electric resistance caused by the wear of the electrically contacting point is prevented. Japanese Unexamined Patent Publication (Kokai) No. 7-224738 discloses the above mentioned fuel injection apparatus.
When the pitch of the injector mounting holes 106 and the pitch of the injector inserting holes 142 are not the same, or when an axis of the injector mounting hole 106 is inclined with respect to an axis of the injector inserting hole 142 even if the pitch of the injector mounting holes 106 and the pitch of the injector inserting holes 142 are the same, the injector 120 is inclined with respect to the axis of the injector mounting hole 106 and is mounted in the injector mounting hole 106. In the fuel injection apparatus disclosed in Japanese Unexamined Patent Publication (Kokai) No. 7-224738, since the injector 120 is held at three points by means of the O-ring 122, the fixing hook 126 and the insulator 128, the injector 120 rotates around the fixing hook 126.
FIG. 16 an enlarged partial sectional view similar to FIG. 15, wherein the injector 120 is inclined with respect to the axis of the injector mounting hole 106 and is mounted in the injector mounting hole 106. As shown in FIG. 16, when the injector 120 is inclined with respect to the axis of the injector mounting hole 106 and is mounted in the injector mounting hole 106, an upper face of the left fixing hook 126 of the injector 120 contacts an upper face of the left fixing hook groove 108 of the delivery pipe 100, and the injector 120 rotates around a contacting point between the upper face of the left fixing hook 126 and the upper face of the left fixing hook groove 108. In this case, the O-ring 122 is biased, and contacting area between the O-ring 122 and the injector mounting hole 106 decreases, and therefore, sealing efficiency of fuel between the delivery pipe 100 and the injector 120 decreases.